\begin{tikzpicture}
    \tkzDefPoints{0/0/B, 3/0/C}
    \tkzDefTriangle[two angles=50 and 70](B,C)  \tkzGetPoint{A}
    \tkzDefPointOnLine[pos=0.7](A,C)  \tkzGetPoint{D}
    \tkzDefPointBy[rotation=center D angle 50](A)  \tkzGetPoint{e}
    \tkzInterLL(D,e)(A,B)  \tkzGetPoint{E}

    \tkzDrawPolygon(A,B,C)
    \tkzDrawSegment(D,E)
    \extkzLabelAngel[0.4](A,D,E){$1$}
    \tkzLabelPoints[above](A)
    \tkzLabelPoints[left](B,E)
    \tkzLabelPoints[right](C,D)
\end{tikzpicture}

